1. Field of the Invention
The present invention relates to a manufacturing method of a pattern formed body which is suitably used to produce a semiconductor element such as a transistor or a diode.
2. Description of Related Art
Conventionally, as a manufacturing method of a pattern formed body capable of forming various patterns such as a design, an image, characters and a circuit, various methods have been suggested.
In particular, as a manufacturing method of a pattern formed body capable of forming, a highly precise pattern, suggested is a method of forming a pattern having a surface of different wettability to a liquid.
Suggested is, for example, a method of forming a transparent electroconductive film into a pattern form on a substrate, forming an insulation film in openings of the transparent electroconductive film by using a material having a variable surface-wettability onto a liquid thin-film material, the wettability being varied by irradiation with light, increasing the wettability of the light-irradiated areas of the surface of the insulation film onto the liquid thin-film material by irradiating the transparent electroconductive film and the insulation film partially and selectively with the light through a photomask, and giving the liquid thin-film material onto the light-irradiated areas of the transparent electroconductive film and the insulation film, thereby forming a thin film into a pattern form (see Japanese Patent Application Laid-Open (JP-A) No. 2004-288469). According to this method, by the irradiation of the insulation film with the light, areas having different wettabilities onto the liquid thin-film material are formed as the film surface, and this wettability difference of the film surface is used to make it possible to form a thin film into a pattern form with a high precision.
Suggested is also a method of causing a substrate on which a liquid repellent layer is formed on a base material and a photomask to adhere closely to each other under a predetermined pressure, radiating light through the photomask onto the substrate to form, forming in the liquid repellent layer, a pre-pattern having different contact angles onto a functional liquid, and supplying the functional liquid onto the pre-pattern to form a minute structure in the part where the contact angle onto the functional liquid is small (see JP-A No. 2008-9321).
Furthermore, suggested is a method of forming a polyimide layer exhibiting hydrophobicity onto a glass substrate exhibiting hydrophilicity, forming a photoresist onto the polyimide layer, patterning the polyimide layer by photolithography to form hydrophilic areas where the glass substrate is uncovered, and hydrophobic areas where the polyimide layer is formed on the glass substrate, and causing an electroconductive material or semiconductor material to adhere onto the hydrophilic areas by ink-jet printing, thereby forming source/drain electrodes (see Japanese Patent Application National Publication (Laid-Open) No. 2003-518756). According to this method, after the patterning of the photoresist in the photolithography, the workpiece is exposed to oxygen plasma, so as to etch the polyimide layer and further make the hydrophilicity of the glass substrate surface high.    [Patent Document 1] JP-A No. 2004-288469    [Patent Document 2] JP-A No. 2008-009321    [Patent Document 3] JP-A No. 2003-518756
In the method described in JP-A No. 2004-288469, in the case of causing the substrate and the photomask to adhere closely to each other at the time of the light irradiation, the highest precision can be obtained; however, the close adhesion causes the photomask to be damaged or polluted. Thus, it is stated that the gap between the substrate and the photomask is preferably made as small as possible. It is also stated that the wettability change caused by the light irradiation depends largely on an effect based on reaction between an oxygen active species near the insulation film and the insulation film surface, and thus the light having wavelengths in the vacuum-ultraviolet wavelength range is preferable.
However, if a space is present between the substrate and the photomask, the following problem is caused: when the workpiece is irradiated with vacuum-ultraviolet ray, the oxygen active species goes around also to the areas not irradiated with the light-ultraviolet light so that an obscure pattern, which is low in precision, is formed. Furthermore, in a case where the resultant pattern formed body is used to manufacture a functional element by forming a thin film on the areas irradiated with the vacuum-ultraviolet ray and subsequently further forming a member on the areas not irradiated therewith (i.e., non-irradiated areas), the following fears arise: when the oxygen active species goes around to the non-irradiated areas during the irradiation with the vacuum-ultraviolet ray, the surface of the non-irradiated area is oxidized with the oxygen active species so that OH groups are formed on the non-irradiated area surface to cause carrier trapping, and additionally the interface between the non-irradiated areas and the member formed thereon turns rough; these matters result in a deterioration in the flatness or the molecular orientation of the laminated molecules so that characteristics of the element are declined.
According to the method described in JP-A No. 2008-9321, the substrate and the photomask adhere closely to each other to have a measure of pressure onto each other, therefore, it scarcely happens that the oxygen active species goes around to the non-irradiated areas by the light. As a result, the boundaries between the liquid repellent areas, which are the irradiated areas, and the lyophilic areas, which are the non-irradiated areas, can be made clear.
However, the method has a problem that the photomask is damaged or polluted as described above since the substrate and the photomask are caused to adhere closely to each other. The method also has a problem that the irradiated areas are not surface-modified or that much time is required to attain the surface modification since the amount of oxygen atom radicals generated by the light is small.
The method described in Japanese Patent Application National Publication (Laid-Open) No. 2003-518756 has a problem that steps based on the polyimide layer are generated so that a method for applying an ink onto the hydrophilic areas is restricted, and a problem that an ink cannot be applied onto a target pattern in accordance with the kind of the pattern.